I'm a novice at this solar stuff. I have not bought the inverter yet because I have no idea what would be overkill or undershooting. Maybe you can clue me in. I understand that the size is based mostly on what or how much equipment is drawing power and how much storage you have. I have two 35a 1000w hr. batteries and that's all. My Scamp trailer has an elect. ref but it can run on propane so I have not considered that as a draw on the system. I have a small microwave , small baking oven, radio, and computer. But they will not all be on at the same time ever. The trailer is used only for long durations while my short tern outings may last 3-6 days and I will use a different vehicle on those outings. with that rig I will only use 50w (2-panels and 1 battery).. I will only need power for the portable refer and I don't want to have to use the vehicle to charge the battery. Someone mentioned a 30w inverter for that, what do you think from your experiences ?